Lighting designers must be able to define and use a dizzying array of technical terms used in the art of theatrical lighting design. As in many languages, the language of lighting design can have some confusing terminology. Some words even have double meanings, and multiple definitions depending on how they are used. It would take a very long article to explain all the technical words used in the theatre. Below are a few of my favorite terms that are sometimes misunderstood.
Additive Color Mixing - This is the way designers mix color in light by combining two or more colors of light in the same area. When two or more wavelengths of colors mix additively, the resulting color is always lighter. When you mix all three primary or secondary colors together at the same intensity, theoretically the resulting color is white.
Atmosphere - This item is used to describe a light cue. It is also used as a general term to describe the density of haze or smoke in the air to reflect light beams.
Automated Light - Also known as "moving light" or "intelligent light" (although I have no idea how a light can be intelligent). This name refers to any fixture where multiple movement parameters can be remotely controlled.
Balcony Rail - A pipe located on the front of the balcony. This position is ideal to fill in the shadows under the eyes with light.
Beam and Field Spreads - The beam of the light is the width from the center of the light (where it is brightest) to the point where the intensity drops off to 50%. The field of the light is the part of the light that is measured from the center of the beam to the point where the intensity drops off to 10%. Due to its' lens arrangement and design, Lekos have predetermined beam and field spreads. The most common are 5, 10, 14, 19, 26, 36, 50, 70, and 90-degree beam spreads, and are identified as such.
Blackout - A lighting cue that brings all the intensity levels to zero. This is usually the light cue placed at the end of the Act or at the end of the show. Shows over!
Bleed Through - This is the effect when light is shifted from the front of a scrim, to the rear of a scrim, illuminating the objects behind the scrim. This can be a powerfully magical effect that makes objects appear behind a curtain.
Booms - These are vertical pipes that are mostly used upstage of the proscenium to provide low to medium side light for the actors. As booms are pipes that are mounted to the floor of the stage, they will block scenic wagons moving on and off stage.
Box Boom - This is a vertical front-of-house lighting position that is located where the audience boxes would be on the left and right sides of the theater. This position is used for front-of-house diagonal side and front light.
Build - A lighting cue that intensifies the atmosphere to support a intensifying mood change or a crescendo in the music.
Bump - A lighting cue on a 0 second count.
Button - A lighting cue that either brightens the overall look or focuses done to a specific point on the stage usually on a very fast count at the very end of a musical number. The times for buttons are usually 0 or 1 second.
Catwalk - This term refers to the bridges used by electricians to hang, circuit, and focus lights. They are usually located above the stage and the audience. For instance, the electricians will use a catwalk to access a front-of-house cove position.
Channel - A predetermined identifier for one or more lighting parameters on a lighting control console. A channel could control intensity, color, pan, tilt, etc, for one or several lighting fixtures. Channel levels are recorded in lighting cues,
Cove - This position refers to the horizontal lighting positions in the ceiling above the audience. This position is sometimes called the "FOH Beam" or "A.P. (anti-proscenium)"
Cue Only - A programming command given after a record command that will record the channel levels in a cue for that cue only. The channels will return to their original levels in subsequent cues.
Delay - A programming command that will delay the execution of a cue or part of a cue after a given time.
Dichroic Filter - Chemically treated glass filter that changes the color of the light by allowing certain wavelengths of light to pass through the glass, and reflecting specific wavelengths of light away from the glass. This color media is used primarily in moving lights. Unlike gels, dichroic filters do not burn or fade.
Once you learn the language of lighting design, you will be able to create and communicate with your fellow theatre artists.
Diffusion - Softening the beam of light through focus or color media.
Electric - This term is used for a batten with electrical circuits on it. Many theaters have predetermined lighting positions with electrical circuits already run.
Fill Lighting - Fill light "fills" in the shadows created by the key lighting, usually at a lower intensity.
Focus - This is a generic term that can be used in several ways. For instance, focusing the lighting refers to the act of actually manipulating the lights to create a lighting effect on stage. The focus of the light can also refer to whether the light is sharp or soft. Finally, focus can refer to where the designer wants the audience to look at the moment.
Focus Point - Designers use focus points to create acting areas in their design. Focus points are also used to preset and reposition moving lights to specific areas of the stage.
Follow - A programming command that automates subsequent cues after the initial cue is executed.
Fresnel - This is the name for the soft wash fixture that has been used for decades. This fixture was named after Augustin Fresnel, the inventor of the cut and ridged lens used in this fixture, and the reason why the Fresnel produces a beautiful soft light. The Fresnel lens originally comes from the inventor's design for lighthouse lenses.
Frost - No, it's not cold outside. Frost is the generic term for diffusion media used to soften the edge of a light. There are many different frost filters available. Some will even alter the shape of the light ("directional frost").
Gel - Color media used to change the color of a lighting fixture. Gel comes from the word "Gelatin", the material first used for flexible color changing. Nowadays, gel is made out of plastics that last a great deal longer than animal gelatin. Gels use subtractive color mixing to change the color of a light. Dichroic Filters are slowly replacing Gels in modern stage lighting fixtures, especially moving lights. Colored LED's may eventually make gels obsolete.
HMI - actually stands for Hydrargyrum Medium-Arc Iodides. But unless you want to sound like Walter White from Breaking Bad, HMI will do. This is a high-intensity arc lamp used in many stage lighting fixtures, usually in very bright moving lights.
Incandescent Lamp - this is the type of lamp used in most conventional lighting fixtures. It creates light through a glowing filament.
Key Lighting - I always teach my students to think about the most important angle of light when creating a lighting atmosphere. The Key light is the most prominent direction of light for that particular atmosphere.
Ladder - Yes, we use ladders onstage to reach and focus lighting fixtures; We also use lighting ladders for lighting positions. Ladders are lighting positions that are usually hung offstage in the wings for sidelight. They resemble ladders with horizontal rungs, so that lights can be mounted on them. They are used instead of booms so that scenery can be rolled on and off stage under them.
Lamp - This is the correct term to use for the electrical device that produces light. It is not a "bulb".
LED - "Light Emitting Diode". A very popular lighting source now used in many stage lighting fixtures, LED's have a very long lamp life and are extremely energy efficient.
Leko - (“Profile Fixture” or “Ellipsoidal Reflector Spotlight”) How many times have we heard this term for an ellipsoidal reflector spotlight? Where did the name Leko come from? Well, the Leko was named after its inventors, Levy and Kook.
Lighting Cue - this refers to an individual "atmospheres" created by the lighting designer and recorded in the lighting desk. Each cue has an in time and an out time, allowing the designer to create timed transitions bridging cues.
Par Can - I always loved this term. We all know that a PAR is a lamp, but where does the "Can" come into it? Well, the "can" is the housing that the PAR lives in so that it can become a lighting fixture. The Par Can is just a metallic housing that protects the electrician from the heat of the lamp. It also has a yoke and c-clamp so that you can mount that fixture to a pipe.
What's the difference between Lighting Beam Spread and Lighting Field Spread?
Parameter - Any item of a lighting fixture or device that can be controlled by a channel. Automated lights can have many parameters that control movement, color, focus, and gobos.
Pipe - Also referred to a “batten” or “system pipe”, this usually refers to a horizontal lighting position connected to the counterweight system placed upstage of the plaster line.
Pipe End – This refers to a light or group of lights placed at the end of an electric or batten. This term also refers to the angle of light produced by this location.
Preset - A recorded position and/or intensities of a group of lights. Presets are used to record positions of moving lights.
Programmer - The person who programs the lighting console.
Proscenium Boom - This position is similar to the box boom, but is located near the proscenium of the theatre, allowing a sharper angle of sidelight.
Pull Down - A lighting cue that focuses the atmosphere down to a specific point on stage. The lighting darkens in areas where the designer does not want the audience to focus on.
Restore - A lighting cue that restores a previous lighting atmosphere.
Scrim - A thin, gauze-like curtain that allows partial lights transmittance. Depending on the type of scrim used, you can create translucent effects depending on how you light objects in the front on and behind the scrim.
Shin Kicker - ("Shin Buster") These are lights hung on the lowest points of a vertical pipe to provide a very low angle of sidelight. This angle is used mainly for dance lighting, but is an increasingly common lighting angle used for traditional theatrical purposes. The name comes from the real danger of dancers running into these fixtures and busting their shins.
Spot Fixture - A lighting fixture that can produce a hard-edged beam, like a Leko or other profile fixtures. These lights can "spot" an actor or other object on stage. You can also insert gobos in many spot fixtures.This term is also used for a Follow Spot, or a moveable profile fixture.
Submaster - Allows the lighting programmer to control separate groups of lights individually from the main playback of the light cues.
Subtractive Color Mixing - This is the way designers mix color in paint. When two colors mix, they subtract the wavelengths and the resulting color is always darker. When the primaries or secondary colors are mixed together evenly; the resulting color is theoretically black. Lighting designers use subtractive color mixing when they place gels in front of a lighting fixture. This is also true when two or more dichroic filters are placed in front of the path of the light.
Track - A programming command given after a record command that will track the channel levels into all subsequent cues until the channel encounters a changed value.
Wash - This usually refers to a "system" of lights that serve one purpose. For instance, you may have a group of lights that create a blue wash.
Wash Fixture - A lighting fixture that can produce a soft-edged beam, like a Fresnel. However, with the right diffusion filter, you can make a Leko look just like a soft edged Fresnel. This is why I always urge my students to use Lekos instead of Fresnels as you have a lot more control over a Leko (through its shutters), and can still are it look like a Fresnel with a frost filter.
Zoom Fixture - A lighting fixture with a variable beam and field spread.
This is only a quick review of lighting terminology for the theatre. Any serious student of lighting design will study the complete glossary of terminology found in many theatrical lighting texts. Once you learn the language of lighting design, you will be able to create and communicate with your fellow theatre artists.
